/*
 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
 * OF SUCH DAMAGE.
 *
 * This file is part of the lwIP TCP/IP stack.
 *
 * Author: Adam Dunkels <adam@sics.se>
 *
 */



/* ip.c
 *
 * This is the code for the IP layer for IPv6.
 *
 */


#include "lwip/opt.h"

#include "lwip/def.h"
#include "lwip/mem.h"
#include "lwip/ip.h"
#include "lwip/inet.h"
#include "lwip/netif.h"
#include "lwip/icmp.h"
#include "lwip/udp.h"
#include "lwip/tcp.h"

#include "lwip/stats.h"

#include "arch/perf.h"

/* ip_init:
 *
 * Initializes the IP layer.
 */

void
ip_init(void)
{
}

/* ip_route:
 *
 * Finds the appropriate network interface for a given IP address. It searches the
 * list of network interfaces linearly. A match is found if the masked IP address of
 * the network interface equals the masked IP address given to the function.
 */

struct netif*
ip_route(struct ip_addr* dest)
{
	struct netif* netif;

	for(netif = netif_list; netif != NULL; netif = netif->next) {
		if(ip_addr_netcmp(dest, &(netif->ip_addr), &(netif->netmask))) {
			return netif;
		}
	}

	return netif_default;
}

/* ip_forward:
 *
 * Forwards an IP packet. It finds an appropriate route for the packet, decrements
 * the TTL value of the packet, adjusts the checksum and outputs the packet on the
 * appropriate interface.
 */

static void
ip_forward(struct pbuf* p, struct ip_hdr* iphdr)
{
	struct netif* netif;

	PERF_START;

	if((netif = ip_route((struct ip_addr*) & (iphdr->dest))) == NULL) {

		LWIP_DEBUGF(IP_DEBUG, ("ip_input: no forwarding route found for "));
#if IP_DEBUG
		ip_addr_debug_print(IP_DEBUG, ((struct ip_addr*) & (iphdr->dest)));
#endif /* IP_DEBUG */
		LWIP_DEBUGF(IP_DEBUG, ("\n"));
		pbuf_free(p);
		return;
	}

	/* Decrement TTL and send ICMP if ttl == 0. */
	if(--iphdr->hoplim == 0) {
#if LWIP_ICMP

		/* Don't send ICMP messages in response to ICMP messages */
		if(iphdr->nexthdr != IP_PROTO_ICMP) {
			icmp_time_exceeded(p, ICMP_TE_TTL);
		}

#endif /* LWIP_ICMP */
		pbuf_free(p);
		return;
	}

	/* Incremental update of the IP checksum. */
	/*  if (iphdr->chksum >= htons(0xffff - 0x100)) {
	  iphdr->chksum += htons(0x100) + 1;
	} else {
	  iphdr->chksum += htons(0x100);
	  }*/


	LWIP_DEBUGF(IP_DEBUG, ("ip_forward: forwarding packet to "));
#if IP_DEBUG
	ip_addr_debug_print(IP_DEBUG, ((struct ip_addr*) & (iphdr->dest)));
#endif /* IP_DEBUG */
	LWIP_DEBUGF(IP_DEBUG, ("\n"));

	IP_STATS_INC(ip.fw);
	IP_STATS_INC(ip.xmit);

	PERF_STOP("ip_forward");

	netif->output(netif, p, (struct ip_addr*) & (iphdr->dest));
}

/* ip_input:
 *
 * This function is called by the network interface device driver when an IP packet is
 * received. The function does the basic checks of the IP header such as packet size
 * being at least larger than the header size etc. If the packet was not destined for
 * us, the packet is forwarded (using ip_forward). The IP checksum is always checked.
 *
 * Finally, the packet is sent to the upper layer protocol input function.
 */

void
ip_input(struct pbuf* p, struct netif* inp)
{
	struct ip_hdr* iphdr;
	struct netif* netif;


	PERF_START;

#if IP_DEBUG
	ip_debug_print(p);
#endif /* IP_DEBUG */


	IP_STATS_INC(ip.recv);

	/* identify the IP header */
	iphdr = p->payload;


	if(iphdr->v != 6) {
		LWIP_DEBUGF(IP_DEBUG, ("IP packet dropped due to bad version number\n"));
#if IP_DEBUG
		ip_debug_print(p);
#endif /* IP_DEBUG */
		pbuf_free(p);
		IP_STATS_INC(ip.err);
		IP_STATS_INC(ip.drop);
		return;
	}

	/* is this packet for us? */
	for(netif = netif_list; netif != NULL; netif = netif->next) {
#if IP_DEBUG
		LWIP_DEBUGF(IP_DEBUG, ("ip_input: iphdr->dest "));
		ip_addr_debug_print(IP_DEBUG, ((struct ip_addr*) & (iphdr->dest)));
		LWIP_DEBUGF(IP_DEBUG, ("netif->ip_addr "));
		ip_addr_debug_print(IP_DEBUG, ((struct ip_addr*) & (iphdr->dest)));
		LWIP_DEBUGF(IP_DEBUG, ("\n"));
#endif /* IP_DEBUG */

		if(ip_addr_cmp(&(iphdr->dest), &(netif->ip_addr))) {
			break;
		}
	}


	if(netif == NULL) {
		/* packet not for us, route or discard */
#if IP_FORWARD
		ip_forward(p, iphdr);
#endif
		pbuf_free(p);
		return;
	}

	pbuf_realloc(p, IP_HLEN + ntohs(iphdr->len));

	/* send to upper layers */
#if IP_DEBUG
	/*  LWIP_DEBUGF("ip_input: \n");
	ip_debug_print(p);
	LWIP_DEBUGF("ip_input: p->len %"U16_F" p->tot_len %"U16_F"\n", p->len, p->tot_len);*/
#endif /* IP_DEBUG */

	if(pbuf_header(p, -IP_HLEN)) {
		LWIP_ASSERT("Can't move over header in packet", 0);
		return;
	}

	switch(iphdr->nexthdr) {
		case IP_PROTO_UDP:
			udp_input(p, inp);
			break;

		case IP_PROTO_TCP:
			tcp_input(p, inp);
			break;
#if LWIP_ICMP

		case IP_PROTO_ICMP:
			icmp_input(p, inp);
			break;
#endif /* LWIP_ICMP */

		default:
#if LWIP_ICMP
			/* send ICMP destination protocol unreachable */
			icmp_dest_unreach(p, ICMP_DUR_PROTO);
#endif /* LWIP_ICMP */
			pbuf_free(p);
			LWIP_DEBUGF(IP_DEBUG, ("Unsupported transport protocol %"U16_F"\n",
			                       iphdr->nexthdr));

			IP_STATS_INC(ip.proterr);
			IP_STATS_INC(ip.drop);
	}

	PERF_STOP("ip_input");
}


/* ip_output_if:
 *
 * Sends an IP packet on a network interface. This function constructs the IP header
 * and calculates the IP header checksum. If the source IP address is NULL,
 * the IP address of the outgoing network interface is filled in as source address.
 */

err_t
ip_output_if(struct pbuf* p, struct ip_addr* src, struct ip_addr* dest,
             u8_t ttl,
             u8_t proto, struct netif* netif)
{
	struct ip_hdr* iphdr;

	PERF_START;

	LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));

	if(pbuf_header(p, IP_HLEN)) {
		LWIP_DEBUGF(IP_DEBUG, ("ip_output: not enough room for IP header in pbuf\n"));
		IP_STATS_INC(ip.err);

		return ERR_BUF;
	}

	LWIP_DEBUGF(IP_DEBUG, ("len %"U16_F" tot_len %"U16_F"\n", p->len, p->tot_len));

	iphdr = p->payload;


	if(dest != IP_HDRINCL) {
		LWIP_DEBUGF(IP_DEBUG, ("!IP_HDRLINCL\n"));
		iphdr->hoplim = ttl;
		iphdr->nexthdr = proto;
		iphdr->len = htons(p->tot_len - IP_HLEN);
		ip_addr_set(&(iphdr->dest), dest);

		iphdr->v = 6;

		if(ip_addr_isany(src)) {
			ip_addr_set(&(iphdr->src), &(netif->ip_addr));
		} else {
			ip_addr_set(&(iphdr->src), src);
		}

	} else {
		dest = &(iphdr->dest);
	}

	IP_STATS_INC(ip.xmit);

	LWIP_DEBUGF(IP_DEBUG, ("ip_output_if: %c%c (len %"U16_F")\n", netif->name[0], netif->name[1], p->tot_len));
#if IP_DEBUG
	ip_debug_print(p);
#endif /* IP_DEBUG */

	PERF_STOP("ip_output_if");
	return netif->output(netif, p, dest);
}

/* ip_output:
 *
 * Simple interface to ip_output_if. It finds the outgoing network interface and
 * calls upon ip_output_if to do the actual work.
 */

err_t
ip_output(struct pbuf* p, struct ip_addr* src, struct ip_addr* dest,
          u8_t ttl, u8_t proto)
{
	struct netif* netif;

	if((netif = ip_route(dest)) == NULL) {
		LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));
		IP_STATS_INC(ip.rterr);
		return ERR_RTE;
	}

	return ip_output_if(p, src, dest, ttl, proto, netif);
}

#if LWIP_NETIF_HWADDRHINT
err_t
ip_output_hinted(struct pbuf* p, struct ip_addr* src, struct ip_addr* dest,
                 u8_t ttl, u8_t tos, u8_t proto, u8_t* addr_hint)
{
	struct netif* netif;
	err_t err;

	if((netif = ip_route(dest)) == NULL) {
		LWIP_DEBUGF(IP_DEBUG, ("ip_output: No route to 0x%"X32_F"\n", dest->addr));
		IP_STATS_INC(ip.rterr);
		return ERR_RTE;
	}

	netif->addr_hint = addr_hint;
	err = ip_output_if(p, src, dest, ttl, tos, proto, netif);
	netif->addr_hint = NULL;

	return err;
}
#endif /* LWIP_NETIF_HWADDRHINT*/

#if IP_DEBUG
void
ip_debug_print(struct pbuf* p)
{
	struct ip_hdr* iphdr = p->payload;

	LWIP_DEBUGF(IP_DEBUG, ("IP header:\n"));
	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	LWIP_DEBUGF(IP_DEBUG, ("|%2"S16_F" |  %"X16_F"%"X16_F"  |      %"X16_F"%"X16_F"           | (v, traffic class, flow label)\n",
	                       iphdr->v,
	                       iphdr->tclass1, iphdr->tclass2,
	                       iphdr->flow1, iphdr->flow2));
	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	LWIP_DEBUGF(IP_DEBUG, ("|    %5"U16_F"      | %2"U16_F"  |  %2"U16_F"   | (len, nexthdr, hoplim)\n",
	                       ntohs(iphdr->len),
	                       iphdr->nexthdr,
	                       iphdr->hoplim));
	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
	                       (ntohl(iphdr->src.addr[0]) >> 16) & 0xffff,
	                       ntohl(iphdr->src.addr[0]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
	                       (ntohl(iphdr->src.addr[1]) >> 16) & 0xffff,
	                       ntohl(iphdr->src.addr[1]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
	                       (ntohl(iphdr->src.addr[2]) >> 16) & 0xffff,
	                       ntohl(iphdr->src.addr[2]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (src)\n",
	                       (ntohl(iphdr->src.addr[3]) >> 16) & 0xffff,
	                       ntohl(iphdr->src.addr[3]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
	                       (ntohl(iphdr->dest.addr[0]) >> 16) & 0xffff,
	                       ntohl(iphdr->dest.addr[0]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
	                       (ntohl(iphdr->dest.addr[1]) >> 16) & 0xffff,
	                       ntohl(iphdr->dest.addr[1]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
	                       (ntohl(iphdr->dest.addr[2]) >> 16) & 0xffff,
	                       ntohl(iphdr->dest.addr[2]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("|       %4"X32_F"      |       %4"X32_F"     | (dest)\n",
	                       (ntohl(iphdr->dest.addr[3]) >> 16) & 0xffff,
	                       ntohl(iphdr->dest.addr[3]) & 0xffff));
	LWIP_DEBUGF(IP_DEBUG, ("+-------------------------------+\n"));
}
#endif /* IP_DEBUG */
